test: Enhance test coverage for PDF conversion tools

[JeevaRamanathan]

Description

• Added new comprehensive test files for txt-to-pdf, jpg-to-pdf, png-to-pdf conversion and improved coverage for remove-blank-page

Coverage Areas

1. Input Validation

   • Empty/null inputs
   • Invalid file types

2. Conversion Process

   • Single file processing
   • Multiple file handling
   • Image dimensions preservation
   • Format-specific features (word wrapping for text, color handling for images)

3. PDF Generation

   • Page creation and layout
   • Content embedding
   • Document properties
   • Output formatting

4. Error Handling

   • File read errors
   • Format parsing failures
   • Resource allocation errors
   • Invalid input recovery

5. UI Feedback

   • Loading state management
   • Progress indicators
   • Error messages

Type of change

• Added new comprehensive test files and updates tests

🧪 How Has This Been Tested?

I tested by changes by executing npm run test:coverage and ensured more than 80% statements are covered

Checklist:

• Verified output manually
• Tested with relevant sample documents or data
• Wrote Vite Test Case (if applicable)

Expected Results:
All test suites achieved greater than 80% statement coverage, meeting quality standards for reliable PDF conversion functionality.

Actual Results:
Achieved more than 80% coverage with well-structured test suites

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[JeevaRamanathan]

Hi @alam00000, could you please review this PR when you get a chance